Lewis & Short

Lāgus, i, m.,

  1. I. the father of Ptolemy I. king of Egypt: regia Lagi, Luc. 10, 527: famosa moenia Lagi, Juv. 6, 83: flumina Lagi, i. e. Nilus, Sil. 17, 592.
    Hence,
  2. II. Lāgēus, a, um, adj., of or belonging to Lagus, Lagian, poet. for Egyptian: Nilus, Luc. 1, 684; cf. amnis, Sil. 1, 196: litora, Mart. 10, 26, 4: ratis, Sil. 10, 322.